Aqueous solubility and Henry's law constant data for PCB congeners for evaluation of quantitative structure-property relationships (QSPRs)

Abstract

Aqueous solubilities and Henry's Law Constants (HLCs) were measured for selected PCB congeners for evaluation of quantitative structure-property relationships (QSPRs) relating chlorine substitution pattern to the chemical parameter. Experimental results were consistent with previously published values. Aqueous solubilities (as solids at 25°C, column generation technique) determined for 26 congeners ranged from 1.08×10 −5 to 9.69×10 −10 mol/L and generally decreased with molecular weight. Values converted to subcooled liquids are also reported. HLCs (25°C, gas purge technique) determined for 20 congeners ranged from 0.3×10 −4 to 8.97×10 −4 atm·m 3/mol. Measured HLCs were not correlated with molecular weight, but increased with degree of orthochlorine substitution within a molecular weight class. Vapor pressures calculated from the product of solubility (mol/m 3) and HLC (atm·m 3/mol) data, generally decreased with molecular weight and increased with increasing degree of ortho- chlorine substitution. Currently available QSPRs were found to be ineffective for predicting solubilities, HLCs and vapor pressures when compared to experimentally determined results. An empirical data fitting approach based on coefficients related to chlorine substitution patterns appears promising.